Automatic electronic and mechanical system to avoid vehicle theft

ABSTRACT

A system to avoid theft of vehicles equipped with internal combustion engines by automatically blocking the fuel flow. This automatic blocking exists every time the engine is turned off or optionally, when any vehicle door is opened while the engine is running.

CROSS-REFERENCE TO RELATED APPLICATION

This invention is disclosed in part in my patent application entitledAUTOMATIC ELECTRONIC AND MECHANICAL SYSTEM TO AVOID VEHICLE THEFT, Ser.No. 945,003, filed Dec. 22, 1986, scheduled to issue on May 24, 1988 asU.S. Pat. No. 4,745,897, the priority of which is claimed for the commonsubject matter.

BACKGROUND OF THE INVENTION

The vehicle anti-theft devices most widely used are of the followingthree types: First, physical blocking, such as a steel rod with a lockfastened from brake pedal to steering wheel; second, electrical blockingto the ignition; and third, alarms.

These systems exhibit to greater or lesser extent the disadvantages thatmost are easily detectable and disconnectable, and most are notautomatic.

One prior art system shuts off the fuel line, as well as having anignition cutoff. This is the Model K 400 FS of Automotive SecurityProducts. It is activated by a visible keypad, containing an owner code.A thief is immediately informed of the protection system by the keypad,and may simply substitute his keypad, with his code to operate thevehicle.

SUMMARY OF THE INVENTION

A system to avoid theft of vehicles equipped with internal combustionengines by automatically blocking the fuel flow. This automatic blockingexists every time the engine is turned off or optionally, when anyvehicle door is opened while the engine is running.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and theapparatus embodying features of construction, combinations of elementsand arrangements of parts which are adapted to effect such steps, all asexemplified in the following detailed disclosure, and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and the objects other than thoseset forth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawings wherein:

FIG. 1 is a diagrammatic view of the invention;

FIG. 2 is a schematic view of the invention;

FIG. 3 shows a modification of FIGS. 1 and 2; and,

FIG. 4 is another modification of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The automatic vehicle anti-theft system which comprises the presentinvention is described herein with respect to one embodiment. Thatembodiment is an attachment to an automotive vehicle having aconventional wiring harness for a battery 50 including a key operatedignition switch S 1 furnishing switched electrical current to theignition, radio, vent, etc.

The present invention includes an electrical module 51 connected byelectrical cable 71 to the positive terminal 64 of the battery 50 and byelectrical cable 72 to the negative terminal 65 of the battery 50. Thepositive terminal 64 of the battery 50 is also connected to key operatedignition switch S 1 supplying switched electrical current to theelectrically controlled fuel supply system 53, the momentary switch S 2and the mode switch box 52.

The momentary switch S 2 is connected by electrical cable 73 to ignitionswitch S 1 and by electrical cable 74 to electrical module 51. Themomentary switch S 2 should be either hidden, such as underneath thedash, or undetectable. It may be any convenient switch, including amagnetic switch, operated by a hand held magnet, a foil or tape switch,operated by finger pressure, or an aperture switch, operated byinserting a pencil point or sharp object into the aperture switch.

The electrically controlled fuel supply system 53 is connected byelectrical cable 75 to ignition switch S 1 and by electrical cable 76 toelectrical module 51. The electrically controlled fuel supply system 53may be a solenoid controlled fuel valve inserted into the fuel line, maybe the motor of an electric fuel pump or may be relay for another fuelcontrol device. In any case, only when electrical current flows throughthe device, does fuel flow to the engine.

Within the electrical module 51 is a SCR Transistor T3 which is anelectronic valve which controls flow of electric current fromelectrically controlled fuel supply system 53, through electrical cable72, to the negative terminal 65 of the battery 50. The momentary switchS 2 is connected to the gate of SCR Transistor T3, through resistors R6,R5, and R1, within electrical module 51.

Also within the electrical module 51 is a NPN transistor T1 whoseemitter is connected to SCR transistor T3 and whose collector isconnected, through electrical cable 72, to the negative terminal 65 ofbattery 50. The base of NPN transistor T1 is connected through biasresistor R4 to the emitter, through resistor R7 and resistor R11, toelectrical cable 77 and the switched electrical current. The base of NPNTransistor T1 is also connected, through resistor R7, to the open doorswitch S 3.

The valet parking override switch S 5, resistor R9, and resistor R10, ofthe mode switch box 52 are all connected by electrical cable 80 throughelectrical module 51, and electrical cable 71 to the positive terminal64 of the battery 50. The electrically controlled fuel supply system 53and the light emitting diode L2 are connected to the SCR transistor T3of the electrical module 51 through electrical cable 79.

Within the mode switch box 52 is a first light emitting diode L1connected through resistor R9 to electrical cable 78 through theelectrical module 51 and electrical cable 71 to positive terminal 64 ofbattery 50. The light emitting diode L1 is also connected throughelectrical cable 78 to electrical module 51 to the anode of SCRtransistor T2, and is a red pilot light. Also within the mode switch box52 is light emitting diode L2 connected through resistor R8 toelectrical cable 77 and the switched electrical current of ignitionswitch S 1. The light emitting diode L2 is also connected to the anodeof SCR Transistor T3, and is a green pilot light.

Referring to FIG. 2, the values of the components may be the following:

R1=150 ohm

R2=360 ohm

R3=1k ohm

R4=2200 ohm

R5=390 ohm

R6=220 ohm

R7=2200 ohm

R8=560 ohm

R9=150 ohm

R10=100 ohm

R11=680 ohm

D1=D2=1N4006

T1=T1P41C

T2=T3=S2800 or C122

The present invention operates in any one of three modes. The first twomodes are protection modes and the third mode is an unprotected mode.

The first, or normal, mode is a combination anti-theft mode andanti-hijack mode. The open door override switch S4 is closed, enablingthe open door switch S 3. The valet parking override switch S5 is open,disabling the valet mode. The owner closes the ignition switch S 1 andpresses the momentary switch S 2. This applies a current to the gate ofSCR Transistor T3, opening the current through the solenoid controlledfuel valve. After the SCR Transistor T3 is turned on, it remains on,until the ignition switch S 1 is opened by turning off the key.

If a thief turns on the ignition switch S 1, but fails to press themomentary switch S 2, the motor will start. However, the electricallycontrolled fuel supply system 53 remains closed and the motor will stopin several seconds for lack of fuel. The switched electrical currentwill be supplied to the electrically controlled fuel supply system 53,but the SCR Transistor T3 will not pass the current. Thus the thief whohas a key will be able to start the vehicle and run a short distance.The motor will then stop. The ignition and starter will work, but thevehicle will give the appearance of an engine malfunction and the thiefwill have to abandon it to avoid apprehension.

In the first, or normal mode, the owner and vehicle are also protectedagainst hijacking by the anti-hijack mode. This mode operatesautomatically by anyone opening a door during operation. If a hijackerforces the owner to open the door, the owner may leave the vehicle. Thehijacker may get into the vehicle and drive away. however, in severalseconds the motor will stop and the hijacker will not be able to restartthe motor.

In the anti-hijack mode, when a door opens, the open door switch S 3 isclosed. This lowers the voltage on the gate of NPN transistor T1. Thisin turn blocks current to flow through NPN transistor T1 which raisesthe voltage on the cathode of SCP transistor T3 which causes SCRtransistor T3 to close. This turns off the electrically controlled fuelsupply system 53, causing the motor to stop. The motor can be restartedonly by closing the door, thus opening the open door switch S 3, andthen by closing momentary switch S 2. Neither the location, nor thefunction of momentary switch S 2 will be apparent to a hijacker.

It will often be convenient to disable the anti-hijack mode to allow theowner to pick up or let off passengers. The vehicle may be operated inthe second of the two protection modes by opening the open door overrideswitch S4. This disables the open door switch S 3 and leaves the NPNTransistor T1 open, so that NPN Transistor T1 cannot turn off SCRTransistor T3 and close the electrically controlled fuel supply system53.

The third mode is the valet mode or unprotected mode. The owner turnsvalet parking override switch S5 on. This supplies current continuouslyto the gate of SCR Transistor T3, effectively grounding the electricallycontrolled fuel supply system 53. The electrically controlled fuelsupply system 53 thus operates whenever the ignition switch S 1 isclosed, and there is no evidence that the vehicle is protected by anautomatic vehicle anti-theft system.

The light emitting diode L2, which may be a green pilot light, is onwhenever the electrically controlled fuel supply system 53 is open,supplying fuel to the engine. The light emitting diode L1, which may bea red pilot light, is on whenever the valet parking override switch S 5is closed and the automatic vehicle anti-theft system is in the valetmode or unprotected mode.

As shown in FIG. 3, a second version of the circuitry allows theinvention to operate with a fuel supply system 53 normally on, so that afailure within the protection system will not cause the vehicle to stop.

Cable 76 from electrical module 51 leads to inverter 85, in order tochange the polarity of cable 86 from negative to positive. Theprotection modes therefore have the polarity not positive for cable 86.

The cable 86 leads to alarm module 87. A presence sensor 88 and opendoor switch S3 also lead to the alarm module 87.

The alarm module 87 is a modification of known vehicle alarm systemssuch as disclosed in Automatic Vehicle Burglar Alarm, PopularElectronics, April 1970, pages 59 et. seq.

The alarm module 87 is connected to the relay 89 which controls thesiren 90, normally open fuel valve 91, and starter 92. A trigger signalfrom open door switch S3 or presence sensor 88 will turn alarm module 87on. A positive signal from inverter 85 will turn alarm module 87 off.

The alarm module 87 has a time delay to allow the operator to leave thevehicle (1 min.) and to reenter the vehicle (6 sec.) before theprotection mode is turned on.

When alarm module 87 activates the protection mode, relay 89 isactivated and siren 90 is turned on, normally open fuel valve 91 isclosed, and starter 92 is disabled.

As shown in FIG. 4, third version of the circuitry allows the inventionto protect fuel injection or turbo engines by turning them off after atime delay, since as soon as the high pressure electric fuel pump isdisabled the engine will stop.

In this version electrical module 51 is connected to a delay module 93,which allows the engine to operate for a period (1 min.) after open doorswitch S3 is closed before relay 94 is activated. When it is activated,it blocks starter 92, fuel injection pump 95 and an optional ignitionblock 96.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in carrying out the above method andin the article set forth without departing from the spirit and scope ofthe invention, it is intended that all matter contained in the abovedescription and shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

What is claimed is:
 1. An automatic vehicle anti-theft system having anantitheft mode and an anti-hijack mode, for a vehicle having both anignition switch S1 and an open door switch S 3 for a door, comprising incombination:(a) an electrically controlled fuel supply system 53supplied with switched electrical current by said ignition switch S 1;(b) a momentary switch S2 supplied with switched electrical current bysaid ignition switch S1; (c) an electronic valve between saidelectrically controlled fuel supply system 53 and the ground; (d) saidelectronic valve normally closed and opened by a voltage applied to itsgate and remaining open thereafter; (e) said momentary switch S2supplying a voltage to the gate of said electronic valve to open saidelectronic valve whenever said ignition switch is on; (f) saidelectronic valve operating a delay module which turns off the fuel pumpafter a preset interval; (g) said open door switch S3 open when the dooris closed and closed when the door is open; (h) said open door switch S3controlling said electronic valve to close said electronic valve whensaid open door switch S3 is closed; (i) an open door override switch S4to selectively disable said anti-hijack mode; and (j) a valet parkingoverride switch S5 to selectively disable the anti-theft mode while thevehicle is in the valet mode; Whereby said automatic vehicle anti-theftsystem permits the owner of said vehicle to disable either of twoprotection modes.